Maintaining vegetation along our highways

Roadside design and construction

The process of keeping the greenery around our highways healthy and safe begins during the design and construction of a new or existing roadway. For information on how WSDOT design and builds roadsides see Roadside and site development. Construction activities sometimes disturb the plants and soils around the worksite. Once construction wraps up, improving the soil and choosing an appropriate plant mix for the roadside take priority.

Ongoing maintenance of roadside vegetation

Our crews take care of the vegetation along the roadside to help travelers see signs, traffic and wildlife. Crews work to remove potentially hazardous trees, control non-native species and establish desirable native plant communities.

Using native plants reduces maintenance and herbicide costs. These species are well-suited to weather and soil conditions, and can grow without constant care. Adding to the natural beauty already found in Washington also controls weeds, which have consequences for farming and native ecosystems, especially pollinators.

An integrated roadside vegetation management plan (IRVM) is a "how to" guide for the best way to manage roadsides in a particular area of the state. Different plans, which include methods and timing, take into account the variety of climates and land uses throughout Washington.

Our vegetation maintenance activities include:

• Mow and trim.
• Selective herbicide use.
• Release weed-eating insects.
• Soil improvement.
• Plant native plants.